The objectives and aims of this application are for San Diego to become the first western United States clinical site in the Pelvic Floor Disorders Network (PFDN). The San Diego Clinical Site is a collaboration of three medical centers: 1) the University of California, San Diego (UCSD), 2) Kaiser Permanente, San Diego (Kaiser) and the 3) Naval Medical Center, San Diego (NMCSD). This same collaboration in the Urinary Incontinence Treatment Network (UITN) led all sites in patient recruitment for the UITN SISTEr (Stress Incontinence Surgery Treatment Efficacy) trial. The efficiency of the San Diego Clinical Site's efforts was recognized by the PFDN and we were asked to become a subcontract site for the University of Alabama for the Colpopexy and Reduction Efforts (CARE) study. In the brief nine months available before the CARE study ended, San Diego (UCSD and Kaiser only) recruited 19 patients to CARE. This total was more than all but one center during those nine months. We were the third UITN site to reach recruitment goals in the UlTN's BE-DRI (Behavior Enhances Drug Reduction Incontinence) study. Additionally in the UITN, our site has led efforts in the design, protocol development, and workgroup leadership for the UlTN's current study, TOMUS (Trial Of Mid-Urethral Slings). Urodynamic studies are commonly performed in the United States at an annual cost of approximately 400 million dollars. These urodynamic studies are routine preoperative investigations in most centers that have urodynamic capability, yet we do not have evidence that these tests improve outcomes. Our concept proposal is a randomized trial of preoperative urodynamic studies in women with predominant stress urinary incontinence. The primary aim is to determine if preoperative urodynamic studies improve treatment success rates in all women considered candidates for SUI surgery after an office evaluation. We believe that this proposed urodynamics study requires a multi-center randomized clinical trial and has significant relevance to the appropriate evaluation and care of women with pelvic floor disorders, namely urinary incontinence. The proposed study also has potential significant importance for national health care resource allocation and expenditures. The work that the San Diego investigators have done for the UITN in the last five years to develop standardized, quality urodynamic studies make them the ideal investigators to lead this effort. We believe that the PFDN will benefit greatly by the proven ability of the San Diego Clinical Site's demonstrated energy, skills, and leadership.